Multisensory instruction is an approach to teaching that engages more than one sense at a time. It incorporates visual, auditory, and kinesthetic-tactile (touch and movement) approaches. Research has shown that this approach helps struggling readers but I've found that it's beneficial for all children. You can use these techniques at home with letter and sound learning or sight words and spelling words.
Notecards with textured letters or words
I made the above letter cards with glitter glue myself for Luke. I found that the bumpiness of the dried glitter in the glue gives enough tactile reinforcement. You can also use Elmer's glue and sprinkle sand on top. Amazon also sells a set if you don't want to make your own.
If you make a set with letters, you can have your child trace the letter and say the sound it makes. I recommend having them trace the letter in the correct way it's written so they learn how to write it correctly.
You can also make a set with the sight words they're working and have your child say the letters in the word as they trace each one and then say the word when they're finished. Like this: "a-n-d and".
Chalk writing
Chalk is great for tactile reinforcement. You can have your child write letters, sight words and spelling words outside on the cement or on a chalkboard.
Shaving cream
Spread shaving cream out in the bathtub or shower and have your child write sight words or spelling words in it.
Sand
Amazon sells a sand tray for this exact use. But you can use the sand in your sand table or sandbox and have your child write letters and words in it.
Stamping
I love this Melissa and Doug stamping letter set for writing words or just practicing letter recognition and sounds. It's a great way to practice and it's fun!